Radio mute during GPS

Hi all!
I am sure this was addressed someplace and I did search and try the Navmute. BUT I still cant get it to work correctly.
I am on win7
using newest RR with elite2 skin
I have GMPC 5.0.70
HD radio. on line in

I added the Navmute to my GMPC and I added the commands to the execTBL.ini